Field of the Invention
The present invention relates to an imprint apparatus and a method of manufacturing an article.
Description of the Related Art
An imprint technique is a technique capable of forming a nanoscale fine pattern, and is receiving attention as one mass production nanolithography technique for semiconductor devices and magnetic storage media. An imprint apparatus using the imprint technique forms a pattern on a substrate by curing an imprint material (resin) in a state in which a mold (original), on which the pattern is formed, and the resin on the substrate contact each other, and then releasing the mold from the cured imprint material. Imprint apparatuses implement various resin curing methods in accordance with application purposes. As a mass production technique for semiconductor devices and the like, a photo-curing method of curing an imprint material on a substrate by irradiation with light such as ultraviolet light is generally employed.
If a gas remains near a mask at the time of filling the pattern (recessed portion) of a mold with an imprint material on a substrate in the imprint apparatus, the pattern formed on the substrate may be distorted. Japanese Patent Laid-Open No. 2007-509769 discloses a technique of decreasing gas pockets present in a resin on a substrate to reduce the distortion of a pattern formed on the substrate. In Japanese Patent Laid-Open No. 2007-509769, the imprint material on the substrate is saturated with a highly soluble gas, a highly diffusible gas, or a highly soluble and diffusible gas such as helium.
As a method for obtaining a state in which a resin on a substrate is saturated with helium, there is known a method of arranging a helium supply nozzle around a mold so as to face a substrate, and substituting (purging) a space between the mold and the substrate with helium. This method can satisfactorily saturate the resin on the substrate with helium.
In the imprint apparatus, not a distortion but a defect (pattern defect) may be generated in a pattern formed on a substrate. For example, if imprint processing is performed in a shot region where particles are attached, a pattern defect is generated in the shot region. If imprint processing is performed in a shot region where large particles are attached, the mold may be damaged. If the mold is damaged, all shot regions having undergone imprint processing using the mold have pattern defects. Thus, it is necessary to minimize the attachment of particles to a substrate, particularly, the attachment of large particles serving as a cause of the damage of the mold. However, there are proposed only few techniques for suppressing the attachment of particles to a substrate in the imprint apparatus, and a concrete measure needs to be presented.